<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /*html{
            font-size:30px;
        }
        .box1{
            width:200px;
            height:200px;
            background-color:orange;
        }
        .box2{
            width:50%;
            height:50%;
            background-color:rgb(214,144,0);
            background-color: rgba(155,0,214,0);
            background-color: #bbffaa;
            background-color: hsl(220, 90%,70%);
            
            background-color: rgb(255,255,255);
            
        }
        .box3{
            width:10em;
            height:10em;
            background-color:aqua;
        }
        .box1{
            width:100px;
            background-color: yellow;
        }
        .box2{
            width:100px;
            background-color: red;

        }
        .box1{
            内容区：元素中所有子元素和文本内容都在内容区中排列，内容区大小由width和height两个属性来设置
            width:200px;
            height:200px;
            background-color:aqua;
            border-width:10px;
            border-color:red;
            border-style:solid;
        }
        .box1{
            color:red;
            width:200px;
            height:200px;
            background-color: orange;
            border-width:10px;
            border-top-width:20Px;
            border-color:aqua;
            border-style:solid;
        }
        .box1{
            border-width:100px;
            border-color:orange;
            border-style:solid;
        }*/
        .box1{
            background-color: red;
            color:red;
            width:200px;
            height:200px;
            border:10px orange solid;
        }

    </style>
</head>
<body>
    <!--<div class="box1">
        <div class="box2"></div>
    </div>
    <div class="box3"></div>
    <div class="box1">我是div1</div>
    <div class="box2">我是div2</div>
    <span>我是span</span>-->
    <div class="box1"></div>
</body>
</html>